Severe wounds are an urgent, unaddressed health need in resource-constrained settings. The incidence of these wounds exceeds 110 million worldwide and is growing due to an increase in diseases associated with chronic wounds—diabetes, cardiovascular disease, and obesity—and an aging global population. In the U.S., conservative estimates exceed $28 billion spent each year treating chronic wounds as a primary diagnosis. In developing world settings, etiological factors that lead to severe wounds are compounded by parasitic, bacterial, viral exposure, and road accidents. In both developed and developing world settings, these open wounds are an enormous cause of morbidity and impose a significant financial burden on patients and their families, especially as non-healing wounds may lead to prolonged disability and prevent a return to employment. The negative socio-economic impact of a chronic wound places a strain on the individual, family, and healthcare system. Without access to adequate wound care treatment in resource-constrained settings, patients suffer from long and costly healing processes. Quality of life is worsened by pain, emotional stress, impaired physical mobility, and often isolation. Direct healthcare costs and opportunity costs in an absence from work and/or loss of employment can devastate a patient's entire family. Hospital systems, outpatient facilities, and home-care settings are burdened with overcrowding and excessive resource requirements.
Therapeutic challenges in wound healing amplify this devastating crisis. Highly orchestrated and specialized procedures are required to treat these chronic wounds. This dynamic process involves the removal of debris, control of infection, reduction of inflammation to clear the area for angiogenesis, deposition of granulation tissue, wound contraction and maturation—a sequence leading to repair and closure. A failure in just one step of this complex process may inhibit healing progression. Neglect present in wound care can lead to further morbidity and increase mortality rates. The cascade effect from infection to systemic complications, extensive hospitalization, amputation and death is inevitable if there is no effective intervention.
The current standard in wound care in many resource-constrained settings is limited to daily gauze dressing wraps and debridement. As gauze dressings are non-occlusive, or permeable to exogenous bacteria, treatment with gauze wraps introduces greater risk of infection, requiring frequent dressing changes and resulting in a prolonged wound healing period. These dressings are also associated with high medical costs, time-consuming care, and patient discomfort.
Negative Pressure Wound Therapy (NPWT) is a clinically validated and market proven method of treating severe wounds. This clinically validated advanced wound management technology addresses the needs of acute, chronic, and postoperative wound care. Typically, the therapy includes a vacuum suction device that applies negative pressure across the surface of a wound through a sealed dressing covering the wound site. The dressing is typically a porous foam or gauze-based material that is fitted to the contours of the wound and covered with an adhesive, airtight film A canister typically connects the dressing and vacuum suction device. A canister is a fluid container that collects and stores fluids pulled out of the wound with negative pressure. The application of continuous negative pressure (suction) over a wound area leads to the removal of exudate (excess fluid), improved vascularization, and creates mechanical forces that stimulate a biological response, leading to significantly faster wound healing. Moreover, NPWT creates a moist microenvironment for the wound, conducive to cell proliferation and migration, angiogenesis, and the elimination of necrotic tissue.
NPWT has been validated as a treatment for a variety of wounds, including pressure ulcers, diabetic foot ulcers, burns and post-traumatic wounds. The role of NPWT in continuous treatment includes a multitude of specific healing-related benefits, such as reduction in wound size and volume as well as decreased healing time for open wounds by a factor of two or more. Blood flow has shown up to a fivefold increase during treatment and edema reduction is significant. Patients treated with a NPWT device, commonly referred to as a “wound vacuum” display higher rates of granulation tissue and up to a threefold increase in expression of enzymes and growth factors at the wound bed. In practice, NPWT is proven to reduce wound-related complications, including infection rate and re-amputations, and increase patient survival when compared to standard treatment. The healing of chronic and acute wounds can be a multi-week or multi-month process, even when NPWT is used. For example, Medicare in the US covers up to four months of treatment with NPWT devices. While NPWT has been shown to be a useful tool in wound care, currently-marketed NPWT products are not aligned with the needs of users in resource-constrained healthcare settings, remote/home use settings and/or low-income population segments. Consequently, currently marketed NPWT devices, including reusable stand-alone devices and portable/disposable devices, may be out of reach financially or difficult to use successfully in these settings. Wound incidence is equivalent if not greater in these patient segments and settings, which underscores a need for technology that can be accessed by these patients and their caregivers.
Reusable, stand-alone NPWT devices are larger systems designed for inpatient settings that can be used many times for repeated treatment and enable healthcare providers to customize the therapy by adjusting a variety of settings. The primary application of this product segment has been the treatment of large non-healing wounds with high volumes of exudate. These reusable stand-alone devices are limited by elaborate user interfaces, complex internal structures (making them susceptible to failures and software bugs), burdensome power requirements and large size. These limitations additionally contribute to a high per device production cost. User interface (UI) complexity in stand-alone devices is evidenced by added features like touch screens and LCD screens, which, while offering a highly customizable treatment regimen, also require users to be trained in device operation and have a moderate level of technological literacy for successful device use and monitoring. UI complexity is further evident in the physical mechanisms used to connect and disconnect device accessories, such as canisters and wound dressings. These mechanisms require adequate physical dexterity from users to twist, orient or locate specific parts in order to make an airtight seal in the system, an essential condition for wound therapy. This can be an obstacle for many wound patients, who often have limited dexterity due to age or co-morbidities. Further, these complex mechanisms are subject to breakage through normal wear and tear or user error, and may be hard to service onsite due to the specific tools, skills and parts required for their repair. The internal apparatuses that constitute current standalone devices feature intricate mechanical and electronic mechanisms. These devices may use a number of electromechanical valves, sensors of various types and microprocessors or microcontrollers for system control in combination with one or more electric vacuum pumps. These components enable high-precision control and monitoring of system pressure and flow rates, but also make the system susceptible to electrical or software bugs, or breakdown of processors or sensors that interrupt the delivery of therapy. Due to these abovementioned factors, often NPWT device manufacturers and suppliers must train personnel extensively to operate and troubleshoot each NPWT device to avoid user errors and/or patient risk. This requirement limits device use to settings with qualified and available trained personnel. Further, standalone devices can only be used in locations with a stable AC power source because components used to create these complex UIs and pressure/flow rate controls draw more power than can be continuously supplied by a single battery or battery pack. These components also make devices large and heavy. Finally, many of these abovementioned limitations have financial consequences for consumers and healthcare providers in that they increase the cost of device production and implementation.
Disposable NPWT devices (single-use) are typically battery-powered highly portable treatment systems that may or may not be re-chargeable. Their UIs are more streamlined, often with a power indicator, power button and no ability to change canisters (e.g. a single-use canister fully enclosed in a device). These devices are typically smaller in size and weight than stand-alone devices. This emerging sector of NPWT devices offers substantial benefits in simplifying treatment, but it is limited to small, fast-healing wounds as the devices typically last only 7 days and can only be used to contain a relatively small amount of exudate (70-300 mL) before needing to be replaced. While these devices have a simplified control UI, they may still have complex attachment mechanisms for accessories that are susceptible to failure, much like stand-alone devices. Additionally, they may have similar internal complexity to stand-alone devices in terms of components used to achieve pressure control, which drives up production cost while making the devices susceptible to software bugs and component failures (e.g. microprocessors, microcontrollers, etc.). Commercially available portable systems address some of the size, complexity and power requirement limitations of standalone devices, to encourage ambulatory patients to move around while receiving treatment. These devices are lower cost and less complex. However, these devices were tailored to exclusively address specific wound types such as acute incision wounds or surgical site infections. This narrower focus limits the indications for use, especially large wounds with high volumes of exudate. Additionally, a shorter useful lifespan makes the devices less economical and practical in chronic wound care.
Within the Disposable NPWT device (single-use) segment, a subgroup of non-electrically powered devices (manual) have been introduced in the marketplace. These non-electric devices provide similar benefits to the aforementioned powered, single-use devices—streamlined UI, portability, reduced production cost. They are also similarly limited in application due to narrower indications for use (e.g. smaller wounds with lower volumes of exudate) and shorter useful lifespan. The manually powered suction apparatus provides an added benefit by reducing reliance on wall and/or battery power and the internal mechanisms for vacuum generation and pressure control do not rely on expensive electrical components (e.g. microprocessors, microcontrollers, etc.). However, the usefulness of manual systems is limited because they are not able to accurately control system pressure, which is a critical NPWT parameter in clinical practice. Though less susceptible to software bugs or electrical component failures, manual devices generate vacuum pressure without any feedback and ability to self-correct if vacuum pressure drops. The manual system requires significant user attention to maintain a vacuum seal and to reestablish clinically appropriate vacuum pressure if pressure is lost for any reason.
Accordingly, there is a need for improved NPWT systems that are robust, reusable, portable, economical, clinically effective, power-efficient and have streamlined interfaces for ease-of-use even among unskilled populations. Finally, both standalone and portable units currently on the market are limited by designs that require a particular brand or type of accessories (waste canister and wound dressing). These units become completely unusable if a single piece of a particular accessory is unavailable or out of supply. This constraint interrupts therapy, drives up prices and makes NPWT infeasible in regions where medical supply chains are frequently interrupted. For these reasons, there remains a need to develop improved solutions that reduce cost, reduce complexity, and increase robustness and accessibility of the therapy to patients.